Key parameters at a glance

A radius of 3.54 Earth radii
A mass of 4.60 Earth masses
Surface gravity around 0.37 g
An orbital period of 278.362 days
Equilibrium temperature 367 K (94 °C)
Distance from Earth 346.67 light-years
Earth Similarity Index 0.468
Travel time at Voyager 1 speed 6,113,489 years

Context from the literature

HIP 41378 d is an exoplanet orbiting around the F-type star HIP 41378. It has a radius about 3.5 times that of Earth. Planetary orbit is significantly inclined to the equatorial plane of the parent star, misalignment been equal to 57.1+26.4−17.9°.

Excerpted from Wikipedia · full article

5 siblings around HIP 41378

HIP 41378 d shares its host star with 5 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HIP 41378 b	Sub-Neptune	2.60	6.89	15.572	959	2016
HIP 41378 c	Sub-Neptune	2.73	4.40	31.706	757	2016
HIP 41378 g	Sub-Neptune	2.54	7.00	62.060	605	2025
HIP 41378 d this	Sub-Neptune	3.54	4.60	278.362	367	2016
HIP 41378 e	Neptune-like	4.92	12.00	369.000	335	2016
HIP 41378 f	Neptune-like	9.20	12.00	542.080	294	2016

HIP 41378 d Planet Profile

Physical Specs

Radius

3.54 R⊕

Radius (Jupiter)

0.316 R♃

Mass

4.60 M⊕

Mass (Jupiter)

0.014 M♃

Density

0.56 g/cm³

Surface Gravity

0.37 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.468

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#158of 1978

top 7.9%

This planet

3.54R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-802 b 3.54 R⊕ Kepler-1316 b 3.54 R⊕ Kepler-1524 b 3.54 R⊕

Metric	Earth	HIP 41378 d	Jupiter
Radius (R⊕)	1.00	3.54	11.21
Mass (M⊕)	1.00	4.60	317.83
Density (g/cm³)	5.51	0.56	1.33
Surface Gravity (g)	1.00	0.37	2.53
Insolation (S⊕)	1.00	3.01	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	4.600 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HIP

HIP 41378

TIC

TIC 366443426

Gaia DR2

Gaia DR2 600698184764497664

Gaia DR3

Gaia DR3 600698184764497664

System

HIP 41378

Percentile among Sub-Neptune cohort

Radius 3.540 R⊕ · percentile 92 / cohort 1978

Mass 4.600 M⊕ · percentile 2 / cohort 1978

Orbital period 278.36 d · percentile 99 / cohort 1946

Distance 106.29 pc · percentile 21 / cohort 1975

ESI 0.468 · percentile 66 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

278.362 days

Semi-major axis

— AU

Eccentricity

0.000

Inclination

89.93 °

Year Length

A year here lasts approximately 278.36 Earth days (76.2% of a terrestrial year) on a nearly circular orbit.

Transit Fingerprint

Duration

12.710 h

Impact parameter b

0.500

Rp / R★

0.025600

Transit midpoint (BJD)

2,457,166.2604

Extended Orbital Architecture

Planet / star radius ratio

0.025600

Semi-major axis / stellar radius

147.030

Impact parameter (b)

0.500

Transit mid-time (BJD)

2,457,166.2604

Sky-projected obliquity (λ)

46.00°

Eq. Temperature

367K

(94 °C)

Insolation (S⊕)

3.01

Earth = 1.00

Earth Similarity (ESI)

0.468

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure.

Discovery Paper

Primary reference

Vanderburg et al. 2016

Instrument

Kepler CCD Array

Publication

2016-08

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at K2 (12 shown).

K2-72 d · Rocky Terrestrial K2-72 b · Rocky Terrestrial K2-91 b · Rocky Terrestrial K2-72 c · Rocky Terrestrial K2-102 b · Super-Earth K2-90 c · Super-Earth K2-72 e · Super-Earth K2-83 b · Rocky Terrestrial K2-88 b · Rocky Terrestrial K2-80 c · Super-Earth K2-83 c · Super-Earth K2-65 b · Super-Earth

Host System: HIP 41378

Spectral Class

F-type yellow-white

Effective Temperature

6,320 K — hotter than the Sun (5,778 K)

Estimated Age

4.28 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.273 R☉

Stellar Mass

1.160 M☉

Metallicity [Fe/H]

-0.10

Extended Stellar Properties

Surface gravity (log g)

4.294 dex

Stellar density

0.680 g/cm³

Systemic radial velocity

50.42 km/s

Rotational v·sin i

5.60 km/s

Activity index (log R'HK)

-4.780

Metallicity ratio

[Fe/H]

Distance

106.29 parsec

Light-years 346.67 ly

V-band magnitude

8.93 mag

Voyager-speed travel 6,113,489 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

9.380 mas

Total Proper Motion

48.143 mas/yr

PM Right Ascension

-48.14 mas/yr

PM Declination

0.06 mas/yr

Galactic Cartesian (pc)

x = -0.587 · y = 0.790 · z = 0.175

Equatorial (J2000)

RA 126.61583° · Dec 10.08037°

Galactic ℓ, b

214.526° · 25.646°

Ecliptic λ, β

126.459° · -8.845°

HTM-20 index

1036383337

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